Five Things to Know About Princess Diana's Stepmother, Raine Spencer — and Why Diana Called Her 'Acid Raine'

Though the cracks in Princess Diana‘s fairy-tale love story have long been made public, it wouldn’t be complete without one particular character: the “wicked” stepmother, Raine, Countess Spencer — who died today at age 87 after a short illness.

Although that’s how their relationship began by many accounts, the real life version was of course far more complicated. Raine became Diana’s stepmother after she married John, Earl Spencer, when Diana was 15 years old. Their relationship was often strained, but the two forged a friendship in the years before Diana’s death.

Raine became Diana’s stepmother after she married Diana’s father, Earl Spencer, in 1976. Ingrid Seward, the Editor-in-Chief of Majesty Magazine tells PEOPLE that things started on a sour note between Raine and Diana.

“Diana couldn’t bear her in the beginning,” Seward says. “Someone as mercurial as Diana was never going to like a stepmother.”

Raine’s connection to Diana, of course, is just one facet in the life of this fascinating women. Among the others:

1. She was born in London to “commoner” parents — but held five titles throughout her life.

Raine Spencer was born Raine McCorquodale in 1929, the only child of Alexander McCorquodale, the heir to a printing fortune as well as an officer in the British Army, and Dame Barbara Cartland, a famed romance novelist.

She was thrice-married and five-times titled: Throughout her life, she held the titles the Honourable Mrs. Gerald Legge, Viscountess Lewisham, Countess of Dartmouth, Countess Spencer and Comtesse de Chambrun. Her first marriage was to Gerald Legge, the future Earl of Dartmouth, with whom she had four children: William, Rupert, Charlotte and Henry. They divorced in 1976, the same year she married her second husband, Earl Spencer.

After he died in 1992, she married again for the final time the next year, to Comte Jean-François Pineton de Chambrun. The two divorced in 1995.

2. She had a famously tense relationship with her stepdaughter, Diana.

After her marriage to Earl Spencer, the family was less than accepting, says Seward, who was a friend of Raine’s. “None of them liked her and they were vile to her,” she says. “Absolutely vile. I think at one point Diana pushed her down the stairs at Althorp. They were really, really, nasty to her.”

Diana’s brother Charles, the current Earl Spencer, said he “didn’t like her one bit,” according to royal biographer Andrew Morton in his book Diana: Her True Story. He also says that the two siblings told their father they’d “wash their hands of them” if he married Raine. After they did marry, Diana and Charles nicknamed their father’s new wife “Acid Raine.”

But as the years went on, Diana’s feelings about her stepmother shifted. Toward the end of Diana’s life, she and Raine became closer, speaking to one another often as Raine became something of a support for Diana. This rapid closeness came in part, due to Diana’s worsening relationship with her own mother, Frances, as well as her growing strain with the royal family.

“When Diana started finding her own mother impossible to deal with, she became extremely friendly with Raine,” Seward says. “They spoke every morning and lunched together once a week or once a fortnight. They were very, very close and Diana used to lean on Raine’s shoulder and tell her all her problems, of which there were many. So their relationship completely turned around. It was quite a dramatic turnaround.”

Charles, on the other hand, maintained a poor relationship with Raine. When their father died in 1992, he reportedly asked her to leave Althorp and she moved into a house in London’s Mayfair neighborhood, which was left to her upon her husband’s death.

3. She was criticized for her running of Althorp, the Spencer family’s ancestral home.

Raine’s marriage to Earl Spencer brought changes not just in the Spencer family, but in their home, too. To economize the goings-on in the house, she laid off staff members and opened the grand estate to the public. These decisions were much like the ones being made by many other aristocratic families at the time, but it was reportedly another cause of tension between Raine and her stepchildren.

Perhaps the move angered Charles and Diana the most was the selling of antiques, furniture and other valuables — according to The Independent, valued at $15 million — that had been owned by the family for years. Not only was it the ridding of these items that disappointed them, but it was what Raine put in their place.

Charles, in fact, said that the new furnishings had “the wedding cake vulgarity of a five-star hotel in Monaco.”

4. Many credit her for nursing her husband, Earl Spencer, back to health after a stroke.

Just two years after she married Earl Spencer, he suffered a massive stroke. Raine spent many hours at his bedside, nursing him back to health in the months and years that followed.

Seward says this was a bit of a turning point in her relationship with Diana.

“Diana really appreciated that she saved her father’s life, really,” she says. “When he had his stroke Raine sat with him in the hospital every day just willing him to live, pulling him through.”

5. She was involved in politics — which is how she met Earl Spencer.

After she married for the first time, to the Honorable Gerald Legge, then the heir to the Earl of Dartmouth, Raine took on a role in local government. Starting at age 23, she became a member of the Westminster City Council (their youngest). She was a conservative.

Her involvement in government stretched out over the next 17 years, with places on several committees, including parks and town planning. Her work in politics hit a high point when she was elected to represent Richmond, a town in London, on the Greater London Council. It was through her government work that she met John Spencer, while they were both on an architectural heritage committee.

Though the origins of their relationship caused a scandal in London at the time — after all, Raine was still married to her first husband — Seward says she was never one to pay much attention to gossip, whether it was about her relationship with Earl Spencer or later on, with her stepdaughter.

“She didn’t mind,” she says. “The people she loved knew the truth and the people who didn’t she didn’t care about. She was very strong.”

WITH REPORTING BY PHIL BOUCHER